Jatropa is failure.
Gentleman,
Jatropa is not failure, we the farmers have failed or the so called businessmen have gained(cheated).
Jatropa as crop in terms of commercials, is not profitable, because of the labor cost that is involved in collecting. if the farmer who grow and do the activities himself, then it may fetch him his salary. but if you employ then it may be insufficient to pay the labor only.
about the question of yield, so many have tried with fertiliser, nutrients and so many thing. in any case a plant will become commercially viable only after 12 to 15 years. until then it is growth of plant only. the yield is gradually increases as the number of branches multiply.
secondly the tendency of the plant is to grow itself(Increase the vegetation), when ever there is plenty of nutrients. plants start produce seeds when there are mature branches or prematurely,when it feels threatened or available energy is not sufficient keep it self alive.
So if you plant and take care of for about 5 years and forget it. and start collect the seeds when it is profitable to do so( As on now available Diesel or crude, is cheaper then the jatropa growing,seed collection,extracting oil and purify to blend with the diesel). Remember, this jatropa oil is only blended with Diesel in minute quantity and not used as fuel as whole. This was introduced to cut the cost of Diesel, then perhaps the economical viability was not properly studied and there was feeling that the crude oil, which we were pumping out from deep earth would be over and there was scarcity of crude at that point of time to justify the extinction.
Even now if something goes wrong with supply of crude, then we all have but no option then finding alternative mode of fuel to run our show.
So never say Jatropa failed. Its failure of human understanding of nature. it is the result of our tendency and eagerness of earning more and more from doing nothing. Its nothing but, compromised humanity.